The present invention relates to a system for processing a document and an image that are associated with color information.
To produce and output a color document or image by a document/image processing apparatus, for instance, to output an image displayed on a CRT with a printer, such a process as converts an additive mixture type color expression of the CRT to a subtractive mixture type color expression of printer inks is required. Conventionally, a system is constructed on the assumption that such processing is performed in each device. Therefore, conversion processes are not unified and a system cannot accommodate a case in which a device is incapable of required conversion between color expressions (see Reference 1).
Among mechanisms for attaining such color coincidence are PostScript Level-2 (Reference 2), SPDL and CES (Reference 2), ODA (Reference 4) and X-CMS (Reference 5).
Each of PostScript Level-2 and SPDL is a PDL (page description language), and they are almost equivalent to each other. In those mechanisms, color specification to realize the color coincidence can be effected in the following manners.
1) Specification in a standard color space of, for instance, CIE.
2) Specification by attaching a description (program) of a conversion procedure to the above color space.
However, in the above mechanisms, color correction processing is required on the PDL creator side, re-editing performance is poor, and it is difficult to accommodate such image input devices as a scanner.
CES ( color encoding standard) prescribes color specification methods for realizing color coincidence in, for instance, InterPress that is a PDL, and realizes color coincidence in a standard color space of, for instance, CIE. However, since a specification method is a subset prescribed in InterPress, an interPress processing mechanism is required and it is difficult to accommodate such image input devices as a scanner which are not related to InterPress.
ODA ( open document architecture ) is a document processing scheme standardized by ISO/CCITT. In ODA, color specification can be effected in the following manners.
1) Specification in a standard color space of, for instance, CIE.
2) Specification by attaching of a description (matrix and LUT) of a conversion procedure to the above color space.
However, like PostScript Level-2 and SPDL, it is difficult for ODA to accommodate to such image input devices which need not deal with ODA.
X-CMS (X-window color management system) is intended to realize faithful color reproduction on a CRT in an X-window system. In X-CMS, color specification to realize the color coincidence can be effected in the following manners.
1) Specification in a standard color space of, for instance, CIE.
2) Specification performed such that a sender (usually an application) requests a receiver (output device, usually a CRT) to supply color correction data on the receiver side and the sender performs a color correction of the receiver side.
However, since X-CMS serves only for window systems and is intended to realize the color coincidence mainly on a CRT, it hardly accommodate such image input devices as a scanner and such image output devices as a printer.